The issues with Novopay are continuing, with many teachers again receiving incorrect wages overnight after months of problems with the new pay system.
Since the Novopay system was launched in August it has been widely criticised for underpaying, overpaying, or not paying some teachers at all.
NZEI national secretary Paul Gaultier says the issues haven't been fixed, and phone lines have been busy this morning with teachers calling to log errors.
Labour's Chris Hipkins this morning warned staff to prepare for another debacle.
"Repeatedly they've given the public assurances that people are going to be paid, and they haven't been."
Mr Hipkins says Associate Education minister Craig Foss ignored poor results from a trial run of the system.
Labour is demanding action from the Government to ensure the Novopay problem is sorted out by Christmas.
"I think teachers and support staff and all those others who rely on Novopay for their pay are entitled to know when they queue up at the supermarkets to buy their Christmas groceries, that their EFTPOS cards aren't going to be declined," says Mr Hipkins.